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Formation of ice eddies in subglacial mountain valleys

Colin R. Meyer; Timothy T. Creyts

Title:
Formation of ice eddies in subglacial mountain valleys
Author(s):
Meyer, Colin R.
Creyts, Timothy T.
Date:
Type:
Articles
Department(s):
Lamont-Doherty Earth Observatory
Volume:
122
Persistent URL:
Book/Journal Title:
Journal of Geophysical Research: Earth Surface
Abstract:
Radar data from both Greenland and Antarctica show folds and other disruptions to the stratigraphy of the deep ice. The mechanisms by which stratigraphy deforms are related to the interplay between ice flow and topography. Here we show that when ice flows across valleys or overdeepenings, viscous overturnings called Moffatt eddies can develop. At the base of a subglacial valley, the shear on the valley sidewalls is transferred through the ice, forcing the ice to overturn. To understand the formation of these eddies, we numerically solve the non-Newtonian Stokes equations with a Glen's law rheology to determine the critical valley angle for the eddies to form. When temperature is incorporated into the ice rheology, the warmer basal ice is less viscous and eddies form in larger valley angles (shallower slopes) than in isothermal ice. We also show that when ice flow is not perpendicular to the valley orientation, complex 3-D eddies transport ice down the valley. We apply our simulations to the Gamburtsev Subglacial Mountains and solve for the ice flow over radar-determined topography. These simulations show Moffatt eddies on the order of 100 m tall in the deep subglacial valleys.
Subject(s):
Geophysics
Eddies
Ice--Dynamics
Glacial landforms
Ice sheets
Publisher DOI:
https://doi.org/10.1002/2017JF004329
Item views
22
Metadata:
text | xml
Suggested Citation:
Colin R. Meyer, Timothy T. Creyts, , Formation of ice eddies in subglacial mountain valleys, Columbia University Academic Commons, .

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